The present invention relates to a high speed printer capable of printing information received from data handling apparatus, such as computers or calculators etc.
With the advent of computer technology and advances in the art of data processing, requirements for increased speed of handling information have become more stringent. One known type of rapid readout with permanent recordation incorporates a high speed printer that employs a character type ball bearing the characters to be printed on the outer surface of the ball. However, a type ball printer has the disadvantages that the printing speed is not sufficient and that a type ball is expensive.
The other prior high speed printer employs a type wheel having the characters to be printed at the outer periphery of respective spokes forming the wheel. The U.S. Pat. No. 3,356,199 is an example of a type wheel printer. However, said type wheel printer has the disadvantage that the number of type characters mounted on a single type wheel is limited. If we want to increase the number of type chatacters, the diameter of the type wheel or the length of the spokes must be increased, but the increase in the diameter of the wheel would increase the inertia of the wheel and reduce it's printing speed. Therefore the upper limit of the number of type characters available on said type wheel printer is only 60 or 70 characters.
In order to overcome the disadvantage of the prior type wheel printer, an improvement on the structure of the spokes of the wheel has already been proposed. In said improvement, a pair of type characters are mounted on a single spoke directly on the straight axis line of the spoke. However, said printer has the disadvantages that the type wheel must be shifted upward and/or downward during the high speed rotation of the wheel, in order to select the desired character from the pair of characters on each spoke, and the up/down shift operation of a wheel reduces substantially the operational speed of the printer. The operational speed of said printer is only 40 chatacters in each second.